Process of electrically heating materials



PATENTED JAN. 19, 1904. A. H. OOWLES. PROCESS OF BLEOTRIGALLY HEATINGMATERIALS.

APPLICATION FILED NOV. 5, 1902.

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UNITED STATES Patented January 19, 1904.

PATENT OFFICE.

ALFRED H. OOVLES, OF CLEVELAND, OHIO.

SPECIFICATION forming part of Letters Patent N 0. 750,095, dated January19, 1904.

Application filed November 5, 1902. Serial No. 130,191. (No model) Toall whom it may concern:

Be it known that I, ALFRED H. OowLEs, a citizen of the United States,residing at Oleveland, in the county of Ouyahoga and State of Ohio, haveinvented certain new and useful Improvements in Processes ofElectrically Heating Materials, of which the following is aspecification.

This invention relates to a process of electrically heating materials,especially mixtures of a metallic compound and a reducing agent, andspecifically to a process of reducing such mixtures as lime and carbonfor the production of calcium carbid. The process contemplates the useas a heating means of a resistance-conductor placed in proximity to thematerials to be heated. This conductor is heated by an electric currentpassed through it, and the density of the current is suitably increasedalong its path, thereby heating the conductor non-uniformly.

The process may be carried out by different forms of apparatus, one ofwhich is shown in the accompanying drawing, in which the figure is avertical axial section of a stack-furnace.

The furnace chosen for illustration comprises a Vertical frusto-conicalstack 1 and a crucible or hearth 2. The stack consists of an iron shell3, having a lining 4 of refractory non-conducting material and awater-jacket 5 surrounding it. The hearth is of refractory conductingmaterial, such as carbon, inclosed in an iron casing 6 and provided witha taphole 7. The top of the furnace is closed by a cover comprising amassive plate of carbon 8 and a carbon ring 21, inclosed by an ironcasing 9. The cover rests on a ring 20, of refractory insulatingmaterial, such as asbestos, which in turn rests upon the upper end ofthe stack. The cover is provided with a central hopper 10 and aplurality of hoppers 11 near its edge, the several hoppers communicatingwith the interior of the furnace through corresponding openings in thecover. A water-jacket 22 surrounds the lower portion of the cover.Secured to the iron casing of the cover is one terminal, 12, of a sourceof electric current, the other terminal, 13, being secured to the ironcasing of the hearth.

In operation loose, broken, or granular refractory conducting material14, such as lumps of coke or carbon, is fed into the furnace through thehoppers 11, and the charge of material to be heated 15 is fed in throughthe central hopper 10. The material 14 arranges itself in a verticallayer surrounding the central column 15 of the material to be heated andconstitutes aresistance-conductor. It will be seen that this tubularconductor, by reason of the conical shape of the stack, decreases incross-sectional area toward the hearth, and its resistance therebyincreases downwardly. When either a direct or alternating current iscaused to pass between the upper electrode or electrodes and the carbonhearth 2 and through the resistance-conductor 14, this conductor isnon-uniformly heated by reason of the gradually-increasing currentdensity toward the hearth. The heat generated by the passage of thecurrent and conducted to the central column of material 15 thusincreases downwardly. By the use of suiiicient current the lower part ofthe resistance-conductor and of the charge within it may be brought toany desired temperature. When the charge 15 consists of a mixture oflime and carbon in proper proportions to form calcium carbid, thetemperature in the charge will be gradually raised as it descends withinthe furnace until the materials reach a zone where they react to formcalcium carbid. This carbid may be allowed to accumulate as a pool inthe hearth and drawn off from time to time through the tap-hole or maybe allowed to run out continuously as produced. The column 15 thereupongradually descends, and fresh material is fed in through the hopper 10.Such portions of the resistance-conductor as are carried down with thecharge may also be replenished through the hoppers 11. The centralcolumn of material is heated not only by radiation and conduction fromthe surrounding resistance conductor, but also by the waste gasespassing up from the Zones of reduction and fusion below.

The furnace shown and described is claimed in my copending application,Serial No. 132,134, filed November 20, 1902.

I claim l. The process of heating materials, which consists in placingthe material in proximity to a resistance-conductor, passing an electriccurrent through said conductor, and increasing the current density alongthe path of the current, through a portion of the conductor in proximityto said material, as set forth.

2. The process of heating materials, which consists in placing thematerial in proximity to a resistance-conductor of loose, broken orgranular material, passing an electric current, through said conductor,and increasing the current density along the path of the current,through a portion of the conductor in proximity to said material, as setforth.

3. The process of reducing a compound, which consists in placing amixture of the compound and a reducing agent in proximity to aresistance-conductor, passing an electric current through saidconductor, and increasing the current density along the path of thecurrent, through a portion of the conductor in proximity to saidmaterial, to a point where the heat generated by the resistance of theconductor effects reduction, as set forth.

4. The process of reducing a compound, which consists in placing amixture of the compound and a reducing agent in proximity to aresistance-conductor of loose, broken or granular material, passing anelectric current through said conductor, and increasing the currentdensity along the path of the current, through a portion of theconductor in proximity to said material, to a point where the heatgenerated by the resistance of the conductor effects reduction, as setforth.

5. The process of producing carbids, which consists in placingcarbid-forming materials in proximity to a resistance-conductor, passingan electric current through said conductor, and increasing the currentdensity along the path of the current, through a portion of theconductor in proximity to said material, to apoint where the heatgenerated by the resistance of the conductor causes the materials toreact to form carbid, as set forth.

6. The process of producing carbids, which consists in placingcarbid-forming materials in proximity to a resistance-conductor ofloose, broken or granular material, passing an electric current throughsaid conductor, and increasing the current density along the path of thecurrent, through a portion of the conductor in proximity to saidmaterial, to a point where the heat generated by the resistance of theconductor causes the materials to react to form carbid, as set forth.

7 The process of producing carbids, which consists in placingcarbid-forming materials in proximity to a resistance-conductor, passingan electric current through said conductor, and increasing the currentdensity along the path of the current, through a portion of theconductor in proximity to said material, to a point where the heatgenerated by the resistance of the conductor causes the materials toreact to form carbid and the carbid to be brought into a moltencondition, as set forth.

8. The process of producing carbids, which consists in placingcarbid-forming materials in proximity to a resistance-conductor ofloose, broken or granular material, passing an elec tric current throughsaid conductor, and increasing the current density along the path of thecurrent, through a portion of the conductor in proximity to saidmaterial, to a point where the heat generated by the resistance of theconductor causes the materials to react to form carbid and the carbid tobe brought into a molten condition, as set forth.

9. The process of producing carbids, which consists in placingcarbid-forming materials in proximity to a resistance-conductor, passing an electric current through said conductor, increasing the currentdensity along the path of the current, through a portion of theconductor in proximity to said material, to a point where the heatgenerated by the resistance of the conductor causes the materials toreact to form carbid and the carbid to be brought into a moltencondition, and tapping off said molten carbid and supplying freshmaterial as required, as set forth.

10. The process of producingcarbids, which consists in placingcarbid-forming materials in proximity to a resistance-conductor ofloose, broken or granular material, passing an electric current throughsaid conductor, increasing the current density along the path of thecurrent, through a portion of the conductor in proximity to saidmaterial, to a point where the heat generated by the resistance of theconductor causes the materials to react to form carbid and the carbid tobe brought into a molten condition, and tapping ofi said molten carbidand supplying fresh material as required, as set forth.

11. The process of heating materials, which consists in placing thematerial in proximity to a resistance-conductor, passing an electriccurrent through said conductor, and increasing the current density in aportion of said conductor, in proximity to said material, therebyheating it ununiformly, as set forth.

12. The process of heating materials, which consists in placing thematerial in proximity to a resistance-conductor of loose, broken orgranular material, passing an electric current through said conductor,and increasing the current density in a portion of said conductor,

in proximity to said material, thereby heats ing it ununiformly, as setforth.

13. The process of reducing a compound, which consists in placing amixture of the compound and a reducing agent in proximity to aresistance-conductor, passing an electric cu rrent through saidconductor, and increasing the current density in a portion of saidconductor in proximity to said material, to a point where the heatgenerated by the resistance of the conductor effects reduction, as setforth.

IIO

14:. The process of reducing a compound, Which consists in placing amixture of the compound'and a reducing agent in proximity to aresistance-conductor of loose, broken or granular material, passing anelectric current through said conductor, and increasing the currentdensity in a portion of said conductor in proximity to said material, toa point where the heat generated by the resistance of the conductoreffects reduction, as set forth.

15. The process of producing carbids, which consists in placingcarbid-forming materials in proximity to a resistance-conductor, passingan electric current through said conduc tor, and increasing the currentdensity in a portion of said conductor in proximity to said material, toa point where the heat generated by the resistance of the conductorcauses the materials to react to form carbid, as set forth.

16. The process of producing carbids, which consists in placingcarbidforming materials in proximity to a resistance-conductor of loose,broken or granular material, passing an electric current through saidconductor, and increasing the current density in a. portion of saidconductor in proximity to said material, to a point where the heatgenerated by the resistance of the conductor causes the materials toreact to form carbid, as set forth.

17. The process of producing carbids, which consists in placingcarbid-forming materials in proximity to a resistance-conductor, passingan electric current through said conductor, increasing the currentdensity in a portion of said conductor in proximity to said material, toa point Where the heat generated by the resistance of the conductorcauses the materials to react to form carbid and the carbid to bebrought into a molten condition, and tapping off said molten carbid andsupplying fresh materials as required, as set forth.

18. The process of producing carbids, which consists in placingcarbid-forming materials in proximity to a resistance-conductor ofloose, broken or granular material, passing an electric current throughsaid conductor, increasing the current density in a portion of saidconductor in proximity to said material, to a point where the heatgenerated by the resistance of the conductor causes the materials toreact to form carbid and the carbid to be brought into a moltencondition, and tapping off said molten carbid and supplying freshmaterial as required, as set forth.

19. The process of heating materials, which consists in placing thematerial in proximity to a resistance-conductor of varying cross-sectionand resistance, and passing an electric current through said conductor,the current density increasing along the path of the current through aportion of the conductor in proximity to said material, thereby heatingthe material non-uniformly, as set forth.

20. The process of heating materials, which consists in placing thematerial in proximity to a resistance-conductor of varying cross-sectionand resistance and of loose, broken or granular material, and passing anelectric current through said conductor and thereby heating the materialnon-uniformly, as set forth.

21. The process of reducing a compound, which consists in placing amixture of the compound and a reducing agent in proximity to aresistance-conductor of varying cross-section and resistance, andpassing through said conductor an electric current of sufficient volumeto effect reduction, as set forth.

22. The process of reducing a compound, which consists in placing-amixture of the compound and a reducing agent in proximity to aresistance-conductor of varying cross-section and resistance and ofloose, broken or granular material, and passing through said conductoran electric current of suflicient volume to effect reduction, as setforth.

23. The process of producing carbids, which consists in placingcarbid-forming materials in proximity to a resistance-conductor ofvarying cross section and resistance, and passing through said conductoran electric current of sufficient volume to cause the materials to reactto form carbid, as set forth.

24. The process of producing carbids, which consists in placingcarbid-forming materials in proximity to a resistance-conductor ofvarying cross-section and resistance, passing through said conductor anelectric current of sufficient volume to cause the materials to react toform carbid and the carbid to be brought into a molten condition, andtapping off said molten carbid and supplying fresh materials asrequired, as set forth.

25. The process of producing carbids, which consists in placingcarbid-formin g materials in proximity to a resistance-conductor ofvarying cross section and resistance and of loose, broken or granularmaterial, and passing through said conductor an electric current ofsuflicicnt volume to cause the materials to react to form carbid, as setforth.

26. The process of producingcarbids, which consists in placingcarbid-forming materials in proximity to a resistance-conductor ofvarying cross section and resistance and of loose, broken or granularmaterial, passing through said conductor an electric current ofsuflicient volume to cause the materials to react to form carbid and thecarbid to be brought into a molten condition, and tapping off saidmolten carbid and supplying fresh materials as required, as set forth.

In testimou y whereof I affix my signature in presence of two witnesses.

ALFRED H. COWVLES.

*itncsses:

F. WV. POWER, 0. J. Fermi.

